The empirical dielectric decay function +(t) = exp -( t / ~~) f i , O< p 9 1 has been transformed analytically and numerically into the frequency dependent complex dielectric permittivity. It is shown that empirical curves give a very satisfactory representation of the dielectric a relaxations observed in polyethyl acrylate, polyvinyl acetate, polyvinyl octanoate, polymethyl acrylate, polypropylene oxide and amorphous polyethylene terephthalate. It is suggested that the present empirical representation is far more satisfactory than existing functions for non-symmetrical loss curves. It is also suggested that the success of the empirical representation may imply that the dipole moment correlation function is a non exponential decay function of time rather than arising from a weighted sum of exponential decay functions. In addition the accuracy of the transformation of transient data into frequency domain data-via the Hamon approximation, is examined for the empirical representation, and it is shown that the transform is accurate for log m0 >0, but significant corrections may have to be applied for / 3 >0.5 and log wz0< 0.

Curcumin nanoparticles of less than 50 nm in diameter are accessible using a continuous flow microfluidic rotating tube processor (RTP) under scalable conditions, at room temperature. A mixture of DDAB and Pluronic F127 renders higher stability of the curcumin nanoparticles in physiological pH 7.4 for up to eight hours. The nanoparticles have enhanced cytotoxicity in estrogens receptor negative and positive breast cancer cell lines compared with free curcumin.

Resonance enhancement of x rays of both odd and even orders has been observed in a thin polymer blend film of polystyrene ͑PS͒ and polybromostyrene (PBr x S) spin cast on a smooth Au layer on a silicon substrate. The x-ray intensity enhancement has been measured by detecting fluorescence from the Br atoms in the PBr x S component of the compatible polymer blend. Analysis of the Br K␣ fluorescence has yielded the PBr x S distribution in the polymer blend layer in agreement with a PS surface enrichment model. PS is largely enriched at the free surface of the polymer layer and partially enriched at the underlying interface.

We present a simple method involving a rotating tube processor to fabricate ultrafine crystalline drug nanoparticles under microfluidic continuous flow with precise control over particle size, with significantly enhanced dissolution of the drug.